Improvement in knives to cut paper bags



UNITED STATES y PATENT OFFICE.

HENRY R. DAVID, oF( NEW YORK, N. Y`

IMPROVEMENT'IN KNIVES TO CUT PAPERA BAGS, 80C.

lSpecification forming part of Letters Patent No. 21,657, dated October 5, 1858.

- ence being had to the accompanying drawings,

making part of this specification, wherein- Figure l is a front elevation of my improved' knife and part of the press used fo'r actuatingI the same. Fig. 2 is an inverted plan of saidv knife. Fig. Sis a plan of the'slot into-which the knife passes,` and Fig. -l is a vertical seotion ofthe knifeandf its bed.

n, Similar marks of reference denotethe sameparts.- 1

My said'invention is intended for `the purpose of cutting out paper bags, although applicable to other characters of work, especially where the cutis not a perfect straight line or where the same has to be done with great dispatch and asmall expenditure of power. The

,shape of the paper as required to be cut out -for making paper bags is shown in Fig. 5, in which anl o'set at an angle of about forty-tive degrees is Ina-dc, to provide -for turning one edge over onto the other and pasting. This shape is cut out of sheets, each adapted to makingone bag; or the knife can be adapted to'form a double cut near the center ot' the sheet united by a short diagonal cut, so as to form two bags ont of one sheet. The knife a is attached to a suitable head-block or follower, b, that is fitted to slide up and down in a competent press, c, and is actuated by a lever. acting on` the toggle-joint d, or equivalent means. eis the bed of the press, in which is an opening, and on the surface of said bedthere is a slotted plate, f, adjustable bycountersunk screws or otherwise, to correspond `with the knife a, so thatsaid knife, when the platen b is brought down, shall pass into said slot. The knife itself is formed of thin steel, l'of the shape required for the cut, and composed of a single piece or separate chiselshaped knives attached to the follower b by screws, and the edges of said knives are formed with nearly semicircular serrations, as seen in Fig.-

1, and properly sharpened; and each alternate serration is longer than the intermediate one, so that as the knife is brought down the long seri-ations pierce and cut first into the paper,

and then the shorter 'serrations operate, cutting the remaining parts thereof. I am thus enabled to obtain a piercing and shearing cut by a vertically-moving knife,` that makes a Iclean cut at --one operation and with little powerjthrough a quire or more of paper, and that without said paper being previously cornpressed, whereas 'if a continuous straightedged k'nife were used it would not cut the paper',- but tear the same and wedge it down into the slot, and require far more power and a sharper instrument than when said knife is formed in the manner set forth.

I do not claima serratededgcd knife in itself. as the same has been used with a reciprocating motion for cutting the edges of books, &c. Neither do I claim a serrated shear or blade for cutting paper, as this has before been used; but i W'hat Iclaim as my invention, and desire to secure by Letters Patent, is-

1. The serrated knife a,.having a vertical movement, in combination with the narrow` slot in the bed-plate f, for sustaining the paper While several thicknesses are being cut for bags HENRY R. DAVID. Witnesses:

LEMUEL W. SERRELL, JAMES S. Dinox. 

